(1) Field of the Invention
The present invention relates in general to orthopedic appliances, and, in particular, to orthopedic appliances having improved moisture management.
(2) Description of Related Art
Orthopedic appliances such as orthoses and prostheses are well known in the art. Prostheses include replacements for missing or amputated limbs. Orthoses include body braces used in the treatment of injured body parts, such as, for example, ankle braces and walking braces. For instance, the intent of an ankle brace is to provide support for an injured ankle while the ankle is healing and to stabilize the ankle against inversion and eversion without restricting plantoflexion and dorsiflexion.
Such ankle braces have utilized a pair of substantially rigid shell members, usually of a stiff, durable, molded plastic material generally shaped to conform to the lateral and medial sides of the lower extremity, respectively. In some cases, a base member, having a pair of hinge portions with distal ends, is formed from a common piece of flexible woven nylon material that has bonded thereon a layer of fastener material such as hook and loop material. The distal ends of the hinge portions are inserted in slots proximal to the lower ends of the shell members and are fastened to an area of mating hook and loop material attached to the inside surfaces of the shell members.
In order to protect the ankle from direct contact with the substantially rigid shell members, it is well known to provide a flexible support member between the ankle and the shell members. See U.S. Pat. Nos. 4,628,945 and 4,280,489, assigned to the assignee herein and incorporated herein by reference in their entireties.
As set forth in commonly assigned U.S. Pat. No. 6,406,450, also assigned to the common assignee and incorporated herein by reference in its entirety, the recovery rate for ankle function following an inversion sprain may be related to the effectiveness of edema control at the injury site. Numerous authors have reported the use of a U-shaped felt or foam rubber device beneath an elastic wrap or adhesive tape for applying focal compression to the soft tissues adjacent to the fibular malleolus. Focal compression involves pressure application to surface concavities of a body part while adjacent proximal convex bony prominences are left uncompressed.
U.S. Pat. No. 3,955,565 discloses an orthopedic apparatus comprising two nesting half shell members that surround a limb. The half-shell members are each provided with columns of apertures hat serve to reduce the weight of the apparatus, to allow longitudinal flexing of the apparatus, and to allow ventilation to the atmosphere. Each shell is provided with one or more air cells, which can include an outer covering or sleeve of absorptive material. These sleeves of absorptive material serve to transfer or wick away moisture that accumulates between the user's skin and the inner surface of the air cell that contacts the user, by directing the moisture from the front of the air cell around the edge of the air cell to the back of the air cell, and then out through the apertures.
In ankle braces, in order to ventilate the affected portion of the ankle, holes have been formed in the rigid outer shell members. Such holes can allow heat that accumulates beneath the shell to vent to the atmosphere, but may not be sufficient to remove moisture that accumulates beneath the shell. Such accumulated moisture can result in unacceptable skin irritation for the user. Another potential problem with such vent holes is that the affected portion of the ankle can be forced outwardly in the areas of the holes, in what is known as “window edema.” This, of course, is an undesirable condition that should not exist in the control and treatment of any body injuries, including ankle injuries.
Thus, it is one object of the invention to provide orthopedic appliances, including orthoses and prostheses, that facilitate the removal of moisture that would otherwise accumulate between the body brace and a user's skin, and preferably that do not promote “window edema” in the user.